JPS59103250A - Electron gun for color picture tube - Google Patents

Abstract

PURPOSE:To extend the diameter of a principal lens and improve focusing characteristic by forming both sided electron beam passing holes of an electrode for the principal lens provided at the bottom of an elliptical cup so that the outside hole can be semicircular and the inside hole can be elliptical and then the central hole can be elliptical. CONSTITUTION:An upper focusing electrode 51 can have longer diameter Dl than a hole pitch S without being restricted by parts work by using the long diameter direction of electron beam passing holes 51A, 51B, and 51C for the short diameter direction of an elliptical cup. As shown in the diagonal view of the upper focusing electrode 51, astigmatism is corrected by leaving behind the edge part on top of the cup and providing first and second curved surfaces 71 and 72 with radius of R, respectively. The size increase of the upper focusing electrode 51 in the horizontal direction is reduced and the deterioration of withstand voltage characteristics can be minimized due to an approach to the bulb neck inner wall. As a result, the diameter of a principal lens can be extended without any problems on the electrode work and side effects such as withstand voltage characteristics. Besides, focusing characteristics can be improved and a clear and sharp picture can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an electron gun for color picture tubes, and particularly to an in-line electron gun for color picture tubes with improved focus characteristics.

[Prior art]

Generally, the main lens aperture of an electron gun for a color picture tube has a great influence on focus characteristics, and in order to obtain suitable focus characteristics, it is desirable to make the main lens aperture as large as possible.

FIG. 1 is a cross-sectional configuration diagram of essential parts showing an example of a conventional pi-potential focusing type in-line electron gun. In the figure, IA, IB, and IC each emit three electron beams from the top surface, 2 is a control electrode that controls the electron beam, and 3 is an accelerating electrode that accelerates the electron beam. There are two lower focusing electrodes each for focusing the beam.
A, 2B.

2C, 3A, 3B, 30 and 4A, 4k1.40 is 3
This is the hole through which the electron beam passes through the book.

5 is an upper focusing electrode, 6 is an anode, and the upper focusing electrode 5 and the anode 6 are provided opposite to each other on the bottom surface fc.
Three choke holes 5A, 5B, 5G and 6 holes.

6B and 6C form a 31' main lens corresponding to three electron beams.

In such an electron gun configuration, three cathodes IA
The three electron beams A, hl, and C, the amount of each of which is controlled by the signal potential applied to , IB, and Ic, are formed between the facing holes of the accelerating electrode 3 and the lower focusing electrode 4. After being subjected to a slight focusing effect by a focusing lens, each main lens formed by an upper focusing electrode 5 and an anode 6 receives a focusing effect so that an image is formed on a fluorescent surface of a picture tube (not shown). At the same time, the electron beams A and C on both sides are given an inclination of an angle θ by a known means of slightly eccentrically eccentricizing the beam passing holes 6A and 6C of the anode 6 outward with respect to the beam passing holes 5A and 50 of the upper focusing electrode 5. ,3
Converge the book's electron beams A, B, and C to the - point.

In the electron gun configured as above, the size of the image point on the fluorescent surface of the picture tube, that is, the focus characteristics, affects the sharpness of the image, so it is desirable to make it as small as possible. Furthermore, in order to improve focus characteristics, the aperture of the main lens is generally increased.

FIG. 2 is a plan view of the vibration section showing the upper surface of the upper focusing electrode 5. FIG. In the same figure, three electron beam passing holes 5A with a diameter
, 5B, , 5C are arranged in a straight line with an interval S, respectively. Further, an electron beam passing hole 5A is provided to enlarge the aperture of the main lens as a means of improving focus characteristics.

It is necessary to increase the diameter of holes 5B and 5C, but each electron beam passing hole 5A, 5B, and 5C needs to have a constricted hole structure to prevent deterioration of the pressure resistance characteristics with the anode 6 shown in Figure 1. However, due to the limitations of the component size, such a constricted hole structure has a diameter of 0.8 to 1. The size is oa+small.

In addition, increasing the hole spacing S increases the convergence error at each point on the fluorescent surface during operation of the picture tube, and also increases the horizontal dimension of the upper focusing pole 5 and the anode 6 that form the main lens. There was a problem in that the voltage resistance became large and the withstand voltage characteristics deteriorated in proximity to the inner wall of the pulp neck in which the electron gun was housed.

[Purpose of the invention]

Therefore, the present invention has been made in view of the above-mentioned conventional problems.The purpose of the present invention is to reduce the above-mentioned side effects, enlarge the lens diameter, and improve focus characteristics for color picture tubes. The goal is to provide electronic guns.

[Summary of the invention]

In order to achieve such an object, the present invention provides a main lens forming method in which the bottom surfaces of an oblong cup having three diaphragm-shaped electron beam passing holes provided in-line in the major axis direction are arranged opposite to each other with an interval. In the electrode, the electron beam passing holes on both sides are irregularly shaped holes with a semicircle on the outside, an oval on the inside, and a circular shape with a notch on the inside. At least one of the cup bottoms is shaped so that the short diameter part of the electron beam passing hole, which is attached to each electron beam passing hole as a circular cutout, covers the circumference of the bottom of the cup, and the distance between it and the counter electrode is wide. It is made with a concave part.

[Embodiments of the invention]

Next, examples of the present invention will be explained in detail using the drawings.

FIG. 3 is a top view of a lower focusing electrode showing an embodiment of a J2FA sub-gun for a collar LF tube according to the present invention.

2 in the same figure, the upper focusing electrode 51 has a central electron beam passage hole 51E with a major axis D! , an oblong aperture hole having a short diameter Ds, and electron beam passing holes 51A on both sides.

Each hole 51C has an irregular shape with a semicircle with radius D/2 on the outside and a semicircle with the same size as the center hole 51B on the inside, and the centers of each hole are arranged at an interval S.

The upper focusing electrode 51 configured in this manner has an electron beam extermination hole 51 in the short axis direction of the oval cup.

By setting the long diameter direction of 51B and 51C, the long diameter Dt can be made larger than the hole pitch S without being subject to restrictions on parts processing. Further, the increase in the horizontal size of the upper focusing electrode 51 also increases the diameter D! Since it is smaller than the case where three circular diaphragm holes are provided, the deterioration of withstand voltage characteristics due to proximity to the inner wall of the valve neck is also minimized. Further, electron beam passing holes 51A, 51B, 51 forming the main lens
Because c is an irregularly shaped hole in which a glazed circle, a semicircle, and a semicircle are connected, astigmatism occurs in which each electron beam has a stronger focusing effect in the short axis direction. As shown in the perspective view of the pole 51, holes 51 on both sides are formed inside each electron beam passage hole, leaving the periphery of the upper surface of the cup.
A, 51C, the first curved surface 71. of radius R. Central hole 51B
By respectively providing second curved surfaces 72 with a radius R, the electric fields formed in the minor axis direction and the major axis direction can be made rotationally symmetrical, and astigmatism can be corrected. Note that in FIG. 4, the shaded portion is for making the shape of the upper surface easier to understand.

FIG. 5 shows an anode 61 similar to the upper focusing electrode 5I.
This figure shows a cross-section of the main parts of an electron gun with the two electron guns arranged facing each other.

In the same figure, the aperture of the main lens is the diameter of each electron beam passing hole 5.
By opening the short diameter side intervals of 1A to 5゛・Ic and 61A to 61C, electron beam passing holes 51A to 510.61
The major diameter D of the circular hole of A to 61C! Since the electron gun is enlarged to a diameter approximately equivalent to that of the electron beam, an electron gun with improved focus characteristics can be obtained without any other side effects.

As a method for converging both (11i1 and Electron beam passage hole 52A.

52E circle 91] By making the circular radius larger than that of the half square circle, the upper surface curvature tK and the thick circle, the center hole 52B
The top surfaces of the holes 52A2 and 52C(1) on both sides are also lowered. In addition, the radial ratio of the central electron beam passage hole 62B of the anode 62 disposed opposite to the upper focusing electrode 52 is
The curvature of the upper surface is made extremely small by making the inner half-circular chambers of both 0111 Hiroko beam passage holes 62A and 62C smaller, and the top surface of the central hole 62B of the anode 62 is made smaller than the inner half-circular chambers of the beam passage holes 62A and 62C. Make it higher than the top. Then, by performing one or both of these means to form a tilted electric field in the main lenses of the electron beams on both sides formed by the electron beam passing holes 52A and 62A, 520 and 62G, the electron beam is directed to the center side. A method of bending and converging may also be used.

FIG. 7 is a plan view of a main part of an upper focusing electrode showing another embodiment of an electron gun for a color picture tube according to the present invention. In the same figure, the central hole 53B of the upper focusing electrode 53 is an oval shape formed by cutting out a circle with a diameter L11 with a width D2 symmetrical to the center line, and the holes 5 on both sides
3A and 53C are D from the center of the circle with diameter 1)+
Even with a configuration in which three electron beam passing holes are provided with the notch 7' (irregularly shaped holes) at 2/2, exactly the same effect as described above can be obtained.

FIG. 8 is a perspective view of a main part of an upper focusing electrode showing still another embodiment of an electron gun for a color picture tube according to the present invention. In the figure, in order to correct astigmatism caused by the three electron beam passing holes 54A, 54B, and 54C of the upper focusing electrode 54, the long axis of the inner cup is A groove with a radius R+ is provided in the direction. In addition, the shaded area indicates the shape of the groove.

With this configuration, the distance between the upper focusing electrode and the anode becomes wider at one point on the blade surface, but the opposing entire circumference blade can be set relatively small, so the valve neck is reduced during the receiving and checking operation. Changes in convergence caused by changes in the internal potential can be prevented.

In the above-described embodiments, the electron beam passing hole, such as a hole formed by connecting an oval shape, a semicircle and a half-width circle, or a hole formed by cutting out an oval and a circular shape, is connected to the upper focusing electrode, the anode, and the like.
It is not necessary to have the same shape and four dimensions within the electrode, and the curvature R may be selected to any value that will correct astigmatism even within the same electrode. Further, the curvature R may be a plurality of curvatures connected or may be an approximate straight line.The tip of the aperture hole may be inclined. In short, the feature is that astigmatism is corrected by configuring the opposing distance between the upper focusing electrode and the anode to be narrow in the major axis direction of the electron beam passage hole and widen in the minor axis direction.

In addition, in the second embodiment described above, a pi-potential focused electron gun was described, but the present invention is not limited to this, and can be applied to other electron guns such as a uni-potential type and a multi-stage Hayabusa type electron gun. Of course, the same effect as described above can be obtained even when applied to a lens.

〔Effect of the invention〕

As explained above, in the electron gun for color image receiving a according to the present invention, the main lens aperture can be enlarged without problems in electrode processing or side effects such as withstand voltage characteristics. This has extremely excellent effects in that focus characteristics are improved and images with high sharpness can be obtained.

[Brief explanation of drawings]

Fig. 1 is a sectional view of main parts showing the structure and operating state of a conventional in-line electron gun, Fig. 2 is a plan view of a swing part showing a conventional upper focusing electrode, and Fig. 3 is a color picture tube according to the present invention. FIG. 4 is a perspective view of the main part of FIG. 3, and FIG. 5 is a plan view of the main part of an embodiment of the upper focusing electrode related to the electron gun, and FIG. FIG. 6 is a sectional view of a main part showing a main lens-field forming electrode configured with an anode facing each other, and FIG. FIG. 7 is a cross-sectional view of the fabrication part showing another embodiment of the constructed Wang Shins electrophoresis forming pole, and FIG. 8 are perspective views showing still another embodiment of the upper focusing electrode of the electron gun for a color picture tube according to the present invention. 4... lower focusing electrode, 51... upper focusing electrode,
51A. 51B, 5IC... are child beam passing holes, 52...
- Upper focusing electrode, 52A, 52B, 52C... Electron beam passing hole, 53... Upper focusing electrode, 53A, 5
3B. 53G... Electron beam passing hole, 54... Upper focusing electrode, 54A, 54B, 54C... Electron beam passing hole, 61... Anode, 61A, 61B, 610...
...Electron beam passing hole, 62...Anode, 62A, 6
2B, 62C...Electron beam passing hole, 71, 72. ,・
·curved surface. -24(

Claims (1)

[Scope of Claims] 1. Two sets of oval cup-shaped electrodes each having cylindrical electron beam passing holes of a number of W arranged in-line in the major axis direction are arranged with a gap between them and their bottom sides facing each other to form opposing electrodes. In an electron gun for a color picture tube, which is provided with a main lens electric field forming electrode that forms a main lens electric field between them, each side hole of the electron beam passing hole has a semicircular shape on the outside and an oval cup-shaped electrode on the inside. The electron beam passing hole in the center is either an oval shape or a circular shape with notches on both sides. A collar characterized in that a concave portion is formed on the bottom surface of at least one cup-shaped electrode so that the distance between the cup-shaped electrode and the opposing electrode is large, leaving a peripheral edge of the bottom surface of the cup-shaped electrode at the short diameter portion of the beam passage hole. Electron gun for picture tube. 2. At least one of the electrodes is configured such that the top of the bottom side of the central electron beam passage hole protrudes toward the cathode side of the high-voltage side electrode with respect to the electron beam passage holes on both sides, and is concave toward the cathode side of the low-voltage side electrode. W of the patent application, characterized in that the electron gun for color picture tubes described in the same item 1.